TGFB1 and neoplasm: To more directly test the possibility that TSCL cells already present in the tumor at the time of TGFβ and PD-L1 blockade have the potential to control tumor growth, mice were treated with FTY720 (daily for three weeks starting when tumors reached ~150 mm3) to block egress of T cells from lymph nodes and prevent tumor infiltration by new circulating cells.